Look at this JavaScript code:

let [CLOSED, OPEN] = [{}, {}];
CLOSED = {
  cake: OPEN,
};
OPEN = {
  fish: 5,
};
console.log(CLOSED); // cake is {}

Why is it that CLOSED is not { cake: { fish: 5 }}?

There is a clear answer, and it’s something worth making sure you understand before heading into a job interview that involves JavaScript.

Emre Tezisci has a pretty good article explaining: APIs vs. SDKs: Key Differences, Use Cases, and Best Practices.

We’re still here to serve developers. And we’re still doing the messy, meaningful work of bridging the gap between what a company thinks developers want and what developers actually need.

I liked the perspective that it’s actually better for a developer advocate to be a little removed from day to day development at the company itself:

… our value often comes because we’re not too close to the implementation. We can see the experience from a developer’s point of view. We notice when onboarding is confusing, when SDKs are missing critical examples, when the documentation skips the “hard but honest” parts.

Some Q&A from Brian Rinaldi on the topic is interesting as well.

Josh Goldberg writes how there is some overlap:

While ESLint and TypeScript operate differently and specialize in different areas of code defects, there is some overlap. Specific types of code defects straddle the line between “best practices” and “type safety,” and so can be caught by both tools.

I could imagine asking (or having to answer) this in a job interview.

The two catch different areas of code defects and come with different philosophies around configurability and extensibility.

• ESLint checks that code adheres to best practices and is consistent, enforcing what you should write.
• TypeScripts checks that code is “type-safe”, enforcing what you can write.

The revenge part? Junior developers, less stuck in their ways, will be quicker to adapt to these new ways of working. I think it’s interesting to think about, but my experience, the value of someone who deeply knows how to understand a system and fix and prevent problems, traits that define a senior developer, will remain as valuable as ever.

A very common answer came up: someone who straddles or bridges the gap between design and development. Someone who can translate for both sides of the coin and also work alongside those parties to achieve the best result for all involved.

You can see respected companies take it seriously like Stripe and Vercel. Maggie Appleton has gathered a group of people who typify it.

If you’re earlier in your career, we just published What Front-End Developer Skills Should You Focus on as Junior Engineer in 2024? — and now we want to do something similar except targeted toward already established developers are on the road towards senior developer.

Here’s the skills we find are in-demand today. This article should serve as a roadmap to getting to the next level.

We also have The Front End Developer/Engineer Handbook 2024, a comprehensive guide to the entire front-end landscape.

Bone Up on Fundamentals & Go Deep

Putting effort into really nailing your understanding of scope, closures, and the event loop can pay off over and over again throughout your career.

JavaScript: The Hard Parts is famous for a reason. No matter where you are in your journey, having a clear mental model of the most popular language under the hood can help you clear up common misconceptions about how things work, and help you write more performant code. And if you want, you can even dive very, very deeply into JavaScript with a series of courses.

Learn Programming Paradigms: Functional and Object Oriented

JavaScript is a “multi-paradigm” programming language, so learning Object Oriented and Functional Programming paradigms will pay off in getting you to the next level. Object Oriented programming is a popular way to structure larger applications. Then add skills to your toolbox from functional programming such as using map, reduce, filter, pure functions and composition.

Ultimately, you’ll want to learn when to use concepts from both Functional and Object Oriented paradigms.

Make Sure You Can TypeScript all the Things

TypeScript has won for teams, so you might as well get great at TypeScript!

Master a Particular Framework

The longer and wider a framework is deployed, the more things like edge cases and performance issues crop up. You should be able to know exactly what your framework of choice helps you with, and where it’s weak points are and how to get around them.

We have a React learning path that dives into all of the idiosyncrasies of the framework. We are starting to do this with Next.js as well.

Design Patterns

Learning to apply common design patterns in your code will help you write more robust web applications. You’ll also develop a more critical eye for recognizing when frameworks and external libraries are useful, and when you might not need that framework.

Performance & Algorithms

Often times what separates a good engineer from a great engineer is being able to know when to make the right trade offs. This goes for choosing tools, as well as when to invest in performance. You can even go as far as diving into the JavaScript Virtual Machine Engine itself if you want to understand what makes code Blazingly Fast.

Knowing how to measure complexity and use the correct algorithms and data structures can lead towards more efficient solutions and better engineering-thinking in general.

Testing, Code Quality, and Tooling

As codebases scale, you need to avoid making regressions when adding new features. You can do that through unit tests, integration, and end-to-end tests using tools like Jest and Playwright.

Learn to set up a suite of testing and code quality tools in the Enterprise UI Development: Testing & Code Quality course.

CSS & Design Tools: Figma, Tailwind, and Design Systems

Having basic design skills can make you a more desirable and well-rounded engineer.

Then on the CSS front, it’s critical to know CSS Grid. Right here on the Frontend Masters site, we are currently revamping several key interfaces like our video player, and I can tell you CSS Grid has helped us simplify complex layouts on several occasions. If you want to practice your CSS skills, you can do that through CSS Projects.

Once you know the fundamental layout techniques, TailwindCSS is becoming standard since it removes the need for naming elements and styling them in separate steps.

Figma for Developers, v2

Figma isn’t just for designers—developers can also leverage its powerful features. Learn to use constraints, layout grids, and auto layout to build responsive designs.

Tailwind CSS

Use Tailwind CSS’s utility-first approach to build out entire web designs without needing any custom CSS! You can even add responsive breakpoints and dark mode right into your HTML markup.

Design Systems with Storybook, v2

Build scalable component libraries and design systems with Storybook. Create reusable UI components with composable styles and variants using Tailwind CSS.

Accessibility

Understanding accessibility is important to making sure your websites are usable by everyone. One type of accessibility is ensuring the site can be navigated and used by keyboard, which is also helpful for some power users who prefer to work that way.

Bonus if you learn tips for making accessible web apps in your framework of choice.

Full Stack: Servers, Deployment, and Building APIs

Learning Node.js and how to build APIs in Node can help you journey towards full-stack development.

Speaking of “full stack” — it’s becoming a more and more common term that developers self-identify as and that shows up on job descriptions. Frontend Masters, despite our name, has content across the stack from front-end to back. You can learn it all here. If you’re doing any build process, API, or server side work, don’t be afraid to use that term for yourself.

Rust and Go are both seeing big lifts in usage for server-side work. Rust a bit more on the tooling side and Go a bit more on the custom servers side.

Basics of Go

Get a quick introduction to Go. Learn basic syntax like variables, constants, data types, and creating and importing packages. You’ll get hands-on with functions, control structures, error handling, type definitions, structures, and interfaces.

The Rust Programming Language

Go from zero Rust knowledge to being able to build your own complete Rust programs! You’ll learn the foundations of Rust, what makes it so performant when to choose to use it for your projects. 

Git

Every major project is in Git and every organization has their own Git-based workflows, expectations, and customs. A senior developer will be expected to know Git well, to the point of helping their co-workers get unstuck with Git issues.

Everything You Need to Know About Git

Expand Your Horizons with Well-Rounded Fundamentals

Go deeper with surrounding topics to round out your knowledge of the fundamentals of full stack and security.

Complete Intro to Containers, v2

Containers are the industry standard for developing and deploying applications. Starting from scratch, you’ll build containers by hand to demystify how they work.

Complete Intro to Linux and the Command-Line

In this course, you will learn powerful commands, use Ubuntu, quit VIM, handle package management, and write your own shell scripts.

Web Security, v2

Gain hands-on experience with security tools and pick up best practices for writing more secure JavaScript in your web applications.

AWS For Front-End Engineers, v2

Learn to build an enterprise-grade deployment infrastructure on AWS. Host your assets on S3 and use CloudFront as a CDN to distribute those assets worldwide in seconds.

Front-End Systems Design

If you’re wanting to become a lead or principle developer with a front-end specialty, you’ll need to have a holistic understanding of what it takes to build scalable web apps.

Front-End System Design

Management

As your career progresses, you may be pushed toward management, or it may appeal to you naturally. First you need to consider if it’s right for you. There is a lot to learn and think about, and we have the perfect course for you here from one of the best in the business.

Engineering Management Fundamentals 101

Are you interested in becoming a team leader or engineering manager? Jem Young, Software Engineer Manager at Netflix, discusses motivations for transitioning into management and confronts hard truths about the position to discover what makes a good manager. 

What do you think?

Which skills do you think developers should be learning as we head into 2025 – what have we missed?